Drafting apparatus



Aug. 30, 1966 A. L. BURNET ETAL 3,268,955

DRAFTING APPARATUS I Filed Feb. 7, 1964 2 Sheets-Sheet 1 INVENTORs flew/me J Eve/v5;-

AQFEEEET [ii 000s ATTORNEYS Aug. 30, 1966 Fiied Feb. 7, 1964 A. L. BURNET ETAL 3,268,955

DRAFTING APPARATUS 2 Sheets-Sheet 2 I NVENTOR S flew/we Z. Bale/var ZZZ flag MM ATTORNEYS United States Patent 3,268,955 DRAFTHNG AlPlPAltATUd Arthur L. Burnet and Herbert .i. Woods, Greensboro,

N.., assignors to Burlington Industries, line, Greenshero, Nil, a corporation of Delaware Filed Feb. 7, 1964, Ser. No. 343,422 8 (Ilaims. (Cl. 119-240} The present invention relates to an improved drafting 'or drawing apparatus or railway head for drafting slivers of textile fibers and, more particularly, to improvements in the means for varying the speed of the front rolls of the drafting apparatus so as to obtain precise tension control of the slivers enabling uniformity in the characteristics of the drafted sliver.

In our copending United States application, Serial No. 199,697, filed June 4, 1962, now United States Patent No. 3,184,798 for A System For Processing Textile Fibers, there is disclosed an apparatus which controls the feeding of the slivers from a plurality of cards to the drafting apparatus or railway head. Additionally, the aforementioned application further discloses a means for sensing variations in physical characteristics of the slivers as they approach the back rolls of the drafting frame and then controlling the speed of such front r-olls so that the variation of the sliver is compensated for or correlated for at the drafting point thereby resulting in uniform characteristics in the drafted sliver.

In the apparatus of the aforementioned application, a variable speed motor is utilized for driving the front rolls whereas a constant speed drive motor is utilized for driving the back drafting rolls. However, such an arrangement has not proven entirely satisfactory at speeds of delivery in the order of 1,000 f.p.m. or greater due to the inability of properly synchronizing the variable speed motor with the constant speed drive motor for particular sliver variations. Additionally, the use of separate sources of power for driving the back rolls and the front rolls necessitated the provision of two motors having different and high starting torques. Because the two motors had different and high starting torques, it was difiicult to obtain a precise control of the delivery speed as very minor changes in speeds of the front rolls could not be easily made.

An object of the present invention is to provide an improved evener motion for a drafting frame which may operate at high speeds and yet in which precise control may be maintained when variations occur in delivery of slivers to the back rolls.

Another object of the present invention is to provide control means for a drafting frame which insures uniformity of output of slivers drafted, the control means utilizing a single main source of power for driving both the back rolls and the front rolls and further including means for varying the speed of the front rolls dependent upon variation in physical characteristics of sliver entering the back rolls, the means independently varying the speed of the front rolls relative the back rolls while the same are still being driven by the single source of power.

Ancillary to the preceding object, it is a further object of the present invention to utilize a main drive motor accepting substantially the entire load for driving both the back and front rolls of a drafting frame and a fractional horsepower variable speed motor for coordinating the variance of speed of the front rolls dependent upon variations of physical characteristics of the sliver entering the back rolls.

Another object of the present invention is to provide an improved evener motion for a drafting frame which is simple and inexpensive to construct, inexpensive to operate, and yet very sensitive even at speeds of delivery of drafted slivers in the order of 1,000 f.p.m. or greater.

These and other objects and advantages of the present invention will appear more fully in the following description, claims and accompanying drawings in which:

FIGURE 1 is a perspective view, somewhat diagrammatic, illustrating the drafting apparatus embodying the present invention, and

FIGURE 2 is an enlarged fragmentary plan View, somewhat diagrammatic, and illustrating the drive for the back and front rolls of the drafting frame of the present invention, as well as the sensing means and the control means for the servo motor controlling the speed of the front rolls.

Referring now to the drawings, wherein like character and reference numerals represent like and. similar parts, FIGURE 1 shows diagrammatically a drafting frame or railway head generally designated by the numeral 10, the drafting frame receiving individual slivers S from a plurality of textile cards (not shown). However, such plurality of slivers could be supplied from a group of cans or other such common feeding devices. The treatment or processing of the slivers S prior to their entering the drafting apparatus 1h may be similar to that disclosed in our aforementioned United States application, Serial No. 199,697 and, therefore, the disclosure of that appli cation :to that extent is incorporated by reference herein. Additionally, details of the drafting frame 10 disclosed in application, Serial No. 199,697 and common to the drafting frame 10 of the present application are incorporated by reference herein.

As shown in FIGURE 1, the several slivers S being lead to the drafting frame 1b in generally side by side relation from separate cards (not shown), are fed through a sensing mechanism 12 just prior to their entering between a pair of back rolls 14. After the slivers pass through the back rolls 14 of drafting frame 10 they then enter and pass through two pairs of intermediate or breakup drafting rolls 16 and 18 respectively, and then pass through a pair of front rolls 20. As is the usual practice in eveners, the back rolls 14 and the intermediate rolls 16 and 18 are each driven at a substantially constant speed but the front rolls 2 0 are driven at a variable speed. In more detail, the peripheral speed of the intermediate rolls 16 while constant is slightly in excess of that of the back rolls 14. The second pair of intermediate rolls 18 have a peripheral speed slightly exceeding that of the first pair of intermediate rolls 16. By having the constant speeds of the back rolls 14 and the intermediate rolls 16 and 18 with the differential constant peripheral speeds, as mentioned above, the slivers S upon passing through the pairs of rolls 14, 16 and 18 are drafted only slightly. On the other hand, the front rolls 20 are driven at a peripheral speed considerably in excess of that of the second intermediate rolls 18 so that slivers are drafted a considerable extent by the front rolls, the location of such greater drafting being at some point between the front rolls and the second intermediate rolls. The exact location of the drafting point depends to some extent on the nature of the fibers being drafted as well as the selected constant speeds for the back rolls 14 and intermediate rolls 16 and 18. For reasons later explained, the front rolls 20 and the calender draw rolls 24 and can 26 are varied in speed during the course of the operation, the speed at any particular time being dependent upon variations in the physical characteristics of slivers as sensed by the sensing mechanism 12.

After the slivers pass through the front rolls 20, they are combined in the usual manner by passing them through a trumpet 22 and calender or delivery rolls 24. The resulting single sliver is neatly coiled by suitable mechanism as it is delivered into a can 26. The can 26 may be of the type which rotates or it may be of the type provided with a rotating coiler wheel and turntable (not shown).

, Referring now in detail to FIGURES 1 and 2, the drafting apparatus 18 is provided with the sensing n1echanism 12 so that a uniformity of thickness or mass per unit length in sliver produced in the drafting apparatus 18 emerges from the trumpet 22. The sensing mechanism 12 senses variations in the thickness of each of the individual slivers S as they approach the drafting frame 18 and the speed of the front rolls 28 is varied so that compensation for an average variation is made during drafting of the slivers. The sensing mechanism 12 may be in the form of a roller 28 having grooves 38 therein for each of the individual slivers S. In order to avoid frictional drag of the roller 28, the roller 28 may be driven in synchronism with the back rolls 14 by providing a stub shaft 32 on one of the back rolls 14, the stub shaft 32 having a sprocket 34 thereon. The roller 28 is provided with a shaft 36 having a sprocket 38 thereon and a chain 40 passing over the sprockets 34 and 38 drives the roller 28 in synchronism with the back rolls 14.

A small roller 42 rides on the sliver S within each groove 39 and is supported on the end of one arm of a bell crank 44 in a manner so that variations in thickness of the sliver S passing between the roller 42 and the bottom of the groove 39 effect swinging movements of the other arm of the bell crank. Connected to the end of such other arm of each bell crank 44, and suitably electrically insulated therefrom, is a variable condenser 4-6 arranged so that its capacitance is varied by swinging movement of the bell crank arm to which it is connected. All of the condensers 46 are connected in parallel, and the parallel connection of the condensers comprises a part of a circuit of a conventional oscillator 48, the frequency of which is varied in accordance with variations in the average capacitance of the several condensers. It will be noted that since the condensers 46 are connected in parallel, the capacitance which controls the frequency of the oscillator, constitutes the average capacitance of the several condensers, so that the electrical signal generated by the oscillator is representative of the average thickness of the several slivers S which may be correlated to the average mass per unit length for the particular slivers being processed.

The signals generated by the oscillator are used to effect changes in speed of the front rolls 20 to increase or decrease the draft effected thereby in a manner to compensate for sensed variations in the thickness of the several slivers S so that a uniform mass or thickness per unit length of the single sliver produced by the drafting frame 10 is maintained. It will be seen that the varia tions are sensed at one location along the length of the travelling slivers S while correction or draft change is applied at another location along the length, i.e., at the draft point which lies somewhere between the front rolls 20 and the sec-nd intermediate rolls 18. Consequently, means must be provided so that there is a time lag between the sensing of a variation of a sliver and the drafting of the sliver in the area where the variation occurs.

In order to obtain such a time lag the electrical signal from the oscillator 48 is received by a recording head 50 and transferred on to an endless moving magnetic tape 52. The signals impressed on and stored in the tape 52 by the recording head 50 are transferred from the tape 52 by a pick-up head 54. The distance between the recording head 50 and pick-up head 54 is so arranged with the speed of the tape 52 to provide a time interval between the recording of a signal at the head 50 and the picking up of the signal at the head 54 which is equal to the time it takes for the sliver to travel from the sensing point or mechanism 28 to the drafting point located between the front rolls 2t and the intermediate rolls 18. As will be explained in more detail later in the specification, the pick-up head 54 will in turn cause either a speeding up or a slowing down of the front rolls 20 as required. A magnetic eraser head 56 of conventional design is located between the pick-up head 54 and the recording head 58 in the direction of travel of the tape so as to erase signals impressed in the tape whereby the tape is free from any magnet impressions when it passes under the recording head 58.

Referring now in particular to FIGURE 2, a constant speed electrical motor 58 is provided for driving the sensing roller 28, the back rolls 14, intermediate rolls 16 and 18 and front rolls 20. In more detail, the electrical motor 58, which operates at a constant speed, drives a drive shaft 60 through a selectively operable speed change unit 62 and a belt or chain drive 64. The drive shaft 68 has a gear 66 thereon meshing with a gear 68 carried on the end of a shaft 70 supporting one of the intermediate rolls 18. A gear drive train 72 between the intermediate rolls 16 and 18 and a gear drive train 73 between the intermediate rolls 16 and the back rolls 14 drives each of these pairs of rolls in synchronism with each other at the desired differential constant speeds referred to hereinbefore. It will now be evident that the drive means for the back rolls 14 and the intermediate rolls 16 and 18 is such that each of these pairs of rolls operates at predetermined constant peripheral speeds, but these speeds may be selectively changed depending upon the type of sliver being processed, merely by manually adjusting the speed change unit 62.

The drive for the front rolls 20 off of the drive motor 58 is accomplished by utilizing a differential unit 74. In more detail, the drive shaft 60 has a bevel gear 76 fixed thereto by a set screw 78. Also mounted on the shaft 60 but rotatable relative thereto, is a second bevel gear 80 having the same axis of rotation as the bevel gear 76 and drive shaft 60. The bevel gears 76 and 80 both mesh with planet bevel gears 82 which are supported within a sun gear 83 for orbital movement about the common axis of the bevel gears 76 and 80. In more detail, the planet bevel gears 82 are carried on shafts (not shown) extending radially between a collar 84 and the inner periphery of the sun gear 83, the collar being rotatably supported on the drive shaft 60. Hence the sun gear 83 is capable of rotating on the same axis as the common axis of the bevel gears 76 and 80 while the planet bevel gears 82 carried by the sun gear orbit about such axis and rotate on an axis radial to the axis of the drive shaft 60. Bevel gear 80 is provided with a collar 86 fixed thereto and rotatably supported on the drive shaft 60, the collar carrying a gear 88 thereon meshing with a gear 90 provided on the end of a shaft 92 supporting one of the front rolls 20. It will now be evident that when the shaft 60 is rotated at a constant speed by the drive motor 58, it will in turn rotate the bevel gear 76 of the differential unit 74. Assuming that the sun gear 83 is held against rotation, then there is a direct drive through the planet gears 82 and bevel gear 80 thus causing the gears 88 and 90 to drive the front rolls 28 at a constant speed. Also, if the sun gear 83 is rotated at a constant speed, then the bevel gear 80 will rotate at a different constant speed.

The sun gear 83 meshes on its periphery with a gear 94 carried on the shaft of a variable speed electrical servo motor 96. The servo motor 96 is operated at a variable speed dependent upon the impulse or signal furnished a servo motor transmitter 98 from an amplifier-rectifier 100. The amplifier-rectifier receives the signal picked up from the magnetic tape 52 by the pick up head 54.

By decreasing or increasing the speed of the servo motor 96, the speed of rotation of the sun gear 83 is varied and thus the output speed of the differential unit 74 as transmitted by the bevel gear 80 is varied so that the speed of rotation of the front rolls 20 is varied.

Since the drive motor 58 assumes substantially all of the torque required to start and drive the front rolls 20, intermediate rolls 16 and 18 and back rolls 14, the S rvo motor 96 may be a fractional horsepower motor as it requires very little energy to rotate and vary the speed of the sun gear 83 and thus vary the speed of the front rolls 20. By utilizing the differential unit '74 driven primarily by the constant speed drive motor 58 to drive the front rolls 20 off the drive shaft 60, and by using the variable speed motor 94 to control the output of the differential unit 74, very accurate and sensitive variations in speed can be made dependent upon variations sensed by the sensing mechanism 12.

It thus will be seen that the objects and advantages of the present invention have been fully and effectively accomplished by the means described above and illustrated in the drawings for providing an evener motion in a drafting frame. However, the present invention has been described in detail for the purposes of illustrating the principles and spirit of the invention but it will be evident that the invention is susceptible to some changes and modifications without departing from such principles and spirit. Therefore, the terminology used in this specification and illustrations in the drawings are for the purpose of description and in limitation, the scope of the invention being defined in the appended claims.

What is claimed is:

1. Drafting means for a sliver of textile fibers comprising: back rolls; front rolls; a single source of power for driving said back rolls at a predetermined constant speed and for driving said front rolls at a different speed relative said back rolls to draft slivers between said front and back rolls; a direct drive operatively connecting said back rolls to said single source of power, said direct drive including a shaft and gearing rotated by said shaft for driving said back rolls; a differential unit operatively connected to said direct drive and driven thereby, said differential unit including a gear fixed to said shaft, a planet gear meshing with the gear fixed to said shaft, a sun gear carrying said planet gear, a second gear meshing with said planet gear, said second gear being operatively connected to said front rolls; sensing means for sensing variations in sliver as it approaches said back rolls; a variable speed motor operatively connected to said sun gear of said differential unit to control the rotational speed of said sun gear so as to vary the speed of said front rolls independently of the single source of power; and means operatively connecting said sensing means to said variable speed motor for coordinating the speed of said variable speed motor with variations sensed in the sliver.

2. The structure defined in claim 1 in which said means operatively connecting said sensing means to said variable speed motor includes means for effecting a time delay between sensing of a sliver variation and varying of the speed of said variable speed motor whereby the varying of the speed of said front rolls occurs at a time when the variation in the sliver has travelled from said sensing means to a drafting point effected by said front rolls.

3. The structure defined in claim 2 wherein said lastmentioned means includes a moving magnetizable means for storing electrical signals representative of sliver variations and means responsive to the signals of said magnetizable means for varying the speed of said variable speed motor.

4. The structure defined in claim 2 in which said single source of power includes a constant speed motor; and selectively operable means in said direct drive for Chang ing the constant speed of said back rolls.

5. In an apparatus for drafting sliver of textile fibers: back rolls; front rolls; a constant speed drive motor; a drive shaft operatively connected to and rotatable by said drive motor; gearing means operatively connecting said back rolls with said drive shaft for driving said back rolls at a constant speed; a first gear fixed to said drive shaft and rotatable thereby; a second gear rotatable about a common axis with said first gear; a third gear meshing with said first and second gears and orbital about the com mon axis of the same, said third gear being rotatable on an axis radial of the common axis of said first and second gears; drive means operatively connecting said front rolls to said second gear; sensing means for sensing variations in sliver as it approaches said back rolls; and controlling means responsive to said sensing means for controlling the orbiting of said third gear to advance and retard the same whereby speed of said front rolls is varied relative to the constant speed of said back rolls dependent upon variations in the sliver.

6. The apparatus as defined in claim 5 wherein said controlling means includes a variable speed servo motor operatively connected to said third gear to move it in orbit, a servo motor transmitter, and a moving magnetizable means for storing electrical signals representative of sliver variations from said sensing means, said servo motor transmitter being responsive to reception of said electrical signals to vary the speed of said servo motor.

7. The apparatus as defined in claim 5 wherein said controlling means includes a fourth gear rotatable on the common axis of said first and second gears, said fourth gear carrying said third gear for orbital movement, a variable speed servo motor for rotating said fourth gear at different speeds, a servo motor transmitter, and a moving magnetizable means for storing electrical signals representative of sliver variations from said sensing means, said servo motor transmitter being responsive to reception of the electrical signals from said magnetizable means to vary the speed of said servo motor.

8. The apparatus as defined in claim 5 including a speed change mechanism interposed between said drive motor and said drive shaft whereby constant speed of said drive shaft may be selectively changed depending upon characteristics of sliver being drafted.

References Cited by the Examiner UNITED STATES PATENTS 2,964,803 12/1960 Robinson 19-240 FOREIGN PATENTS 779,197 7/1957 Great Britain.

MERVIN STEIN, Primary Examiner.

P. C. FAW, Assistant Examiner. 

1. DRAFTING MEANS FOR A SLIVER OF TEXTILE FIBERS COMPRISING: BACK ROLLS; FRONT ROOLS; A SINGLE SOURCE OF POWER FOR DRIVING SAID BACK ROLLS AT A PREDETERMINED CONSTANT SPEED AND FOR DRIVING SAID FRONT ROLLS AT A DIFFERENT SPEED RELATIVE SAID BACK ROLLS TO DRAFT SLIVERS BETWEEN SAID FRONT AND BACK ROLLS; A DIRECT DRIVE OPERATIVELY CONNECTING SAID BACK ROLLS TO SAID SINGLE SOURCE OF POWER, SAID DIRECT DIRVE INCLUDING A SHAFT AND GEARING ROTATED BY SAID SHAFT FOR DRIVING SAID BACK ROLLS; A DIFFERENTIAL UNIT OPERATIVELY CONNECTED TO SAID DIRECT DRIVE AND DRIVEN THEREBY, SAID DIFFERENTIAL UNIT INCLUDING A GEAR FIXED TO SAID SHAFT, A PLANET GEAR MESHING WITH THE GEAR FIXED TO SAID SHAFT, A SUN GEAR CARRYING SAID PLANET GEAR, A SECOND GEAR MESHING WITH SAID PLANET GEAR, SAID SECOND GEAR BEING OPERATIVELY CONNECTED TO SAID FRONT ROLLS; SENSING MEANS FOR SENSING VARIATIONS IN SLIVER AS IT APPROACHES SAID BACK ROLLS; A VARIABLE SPEED MOTOR OPERATIVELY CONNECTED TO SAID SUN GEAR OF SAID DIFFERENTIAL UNIT TO CONTROL THE ROTATIONAL SPEED OF SAID SUN GEAR SO AS TO VARY THE SPEED OF SAID FRONT ROLLS INDEPENDENTLY OF THE SINGLE SOURCE OF POWER; AND MEANS OPERATIVELY CONNECTING SAID SENSING MEANS TO SAID VARIABLE SPEED MOTOR FOR COORDINATING THE SPEED OF SAID VARIABLE SPEED MOTOR WITH VARIATIONS SENSED IN THE SLIVER. 